Road expansion joint



Jan. 24, 1939. RR'ROBERTSON 7 2,144,814

m 0 PM WMM/ Patented Jan. 24, 1939 UNITED STATES ROAD EXPANSION JOINTRobert R. Robertson, Chicago, Ill., assignor to The Translode JointCompany, Chicago Heights, 111., a corporation of Illinois ApplicationJune 13, 1936, Serial No.'85,058

4 Claims.

The present invention relates to concrete construction joints, and moreparticularly to a road expansion joint disposed between adjacentconcrete road slabs, with said joint including in combination, anassembled core unit or joint forming mechanism comprising pre-castplastic filler boards, which are held in offset vertical planes by meansof improved slidably interfitting load transmitting sections consistingof ofiset upper and lower plates or flanges, which are integrallyconnected by means of an S-shaped intermediate portion comprisingchannels or loops connected by means of a common plate of a widthgreater than the combined width of the two loop portions, for thepurpose of bridging the space between the two offset portions of theload transmission joint, and furthermore separating overlapping portionsof the road slabs formed on opposite sides of the joint mechanism toprovide a road construction which will withstand greater stresses andstrains than a road formed with load transmission joints, wherein thecore boards are positioned above one another in substantially the sameplane.

It is an object of this invention to provide an improved road expansionjoint mechanism com prising an adjustable load transmission shielddevice consisting of slidably interfitting sections, which are so formedthat they provide offset pockets projecting in opposite directions forthe purpose of engaging over and holding joint core boards in oiisetvertical planes.

Another object of the invention is the provision of an improved roadexpansion joint forming device, including a shield device formed toprovide ofiset upper and lower pockets for holding core boards in offsetrelation on opposite sides of the vertical center plane of the roadexpansion joint, and including slidably contacting plates which crossthe center plane of the joint and separate overlapping portions of theconcrete construction slabs between which the expansion joint isimbedded.

It is also an object of this invention to provide a concreteconstruction consisting of concrete slabs separated by means of anexpansion joint mechanism, including interfitting metal supports havinganchoring means formed thereon, and furthermore having oifset core boardsupports which are connected by plate members separating overlappingportions of. the road slabs at the center plane of the joint, providingan arrangement whereby stresses applied to one of the road slabs may bereadily transmitted to an adjacent slab, with the receiving slababsorbing the greater.

part of .the load.

It is also an object of this invention to provide a road expansion jointforming device in the form of a unit adapted to be set up on a roadsubgrade for the separation of concrete road slabs, said deviceconsisting of assembled preformed plastic core boards held'in offsetrelation by load transmission devices which interfit one another and areanchored in the adjacent road slabs, said load transmission devicesadapted to be held in assembled relation with the core boards upon aroad subgrade by means of a plurality of spaced holders which are stakedin position in staggered relation on oppositesides of the joint formingmechanism, and include a base plate extending from the bottom of oneroad slab across the bottom of thejoint and beneath the opposite roadslab.

It is an important object of this invention to provide a road expansionjoint mechanism for imbedding between concrete road slabs, saidmechanism consisting of either single or multiple sets of slidablyinterfitting core board supporting sections which are so arranged thatthe core boards are held in staggered or ofiset planes between theinterfitting sections which are provided with anchoring means foranchoring the sections in the oppositely positioned road slabs, whichalso imbed holders for the load transmission mechanism during thepouring of the concrete slabs, said holders being constructed to conformto the shape of the joint and include base plates extending across thebottom of the joint beneath the two adjacent road slabs.

Other and further important objects of this invention will be apparentfrom the disclosures in the specification and the accompanying drawings.

The invention (in preferred forms) is illustrated in the drawings andhereinafter more fully described.

On the drawings:

Figure 1 is a fragmentary perspective view of an improved expansionjoint forming mechanism embodying the principles of this invention, andhaving associated therewith improved holders for staking the jointforming mechanism in position upon a road subgrade preliminary to thepouring of concrete for forming the road slabs.

Figure 2 is a fragmentary vertical detailed section taken onsubstantially line IIII of Figure 1, and illustrating the loadtransmission joint forming mechanism imbedded in the concrete formingroad slabs on opposite sides of the joint. Figure 3 is a' verticaldetailed section of a modified form of load transmitting expansionanother modified form of load transmitting expansion joint mechanismimbedded in the concrete forming opposite road slabs, separated byoffset core boards held in position by means of the interfitting loadtransmitting shield sections, which are formed to hold the upper andlower core plates with the adjacent edges thereof slightly overlappingeach other.

Figure 5 is a fragmentary vertical detailed section through anothermodified form of an expansion joint forming mechanism including a springsteel insert plate.

As shown on the drawings:

The road expansion joint, as illustrated in .Fig ures 1 and 2, is formedby .means of the joint forming unit illustratedin Figure .1 before beingimbedded between concrete road slabs. The various members comprising thejoint forming unit may be assembled and tied together and then shippedto locations ready to .be placed in position upon the road subgrade,orthe various members forming the jointiorming-unitmay be assembled on ajob andsecured in place to permit concrete to be poured on oppositesides-of the joint forming unit.

The improved joint forming uni-tillustrated in Figures 1 and 2:comprises a pre-iormed compressible bottom filler or core board 1 andan upper filler or core board 2 adapted to be constructed of asphalt,sponge-rubbencork or any other suitable compressible :material, such forexample as thecompressible .mater-ial known to the trade as Flexceli.The-two filler or core boards 1 and -2 are positioned -atdifierentlevels, and are furthermore disposedin difierent verticalplanes in an offset relation. The two core boards i and 2 are held inoifset or staggered :relation with respect to one another, by means vof.improved load transmission devices comprising two reversedidentically'constructed sections formed out of sheet metal. Each of .the.metal sections comprises plates or flangesBFa-nd .4, each of which hasstruck outwardly therefrom tapered anchoring blades or wings .5. Theouter ends of the anchoring blades 5 are wider than theinner endstoserve as wedge or anchoringimeans when .the expansion joint device isimbedded in concrete. The anchoring blades of one of the sections arestaggered with respect to the anchoring blades of the opposite section.v

The section plates or flanges 3 and 4 are'held in spaced offset relationwith respect to one another by the middle portion of the section, whichisalso constructed of sheet metal bent or formed to provide anintermediate S-section of alarge loop or channel 6 and a smaller orthinner loop or channel 'l, which project outwardlyawayfrom one anotherin opposite directions. One margin of the plate or flange 3 isintegrally connected with the margin of one of the platesforming theloop'portion 6, while the plate or flange 4 is integrally connected withone margin ofone ofthe plates forming a part of the thinner loop 1. Thetwo remaining plates of theloop portions'li and I are integrallyconnected by a transverse connecting plate 8, which is of such a widththat the flanges 3 and 4 are held in spaced-or'offsetparallel planes,

As clearly illustrated in Figure l, the two metal sections are reversedwith respect to one another, with the narrow channel or loop I of one ofthe sections slidably interfitting into the wider channel or loop 6 ofthe adjacent section. This slidable interfitting relation of the metalsections positions the connecting plates 8 in slidable contactingengagement with one another, providing a double thickness of themetalin-the space separating the two core board holders which are formed bythe flanges 3 and 4 of the interfitting sections.

It will .be noted that the formation of the core board holders is suchthat the holders project in opposite directions from the contactingplates 8, and serve to hold the core boards or fillers in offset spacedrelation in substantially parallel planes.

For the purpose of holding the expansion joint forming mechanism inposition upon a road subgrade, a plurality of holding brackets are:positioned in staggered interfitting relation on :opposite sides of thejoint mechanism and are staked in position. Each of'the expansion jointholders comprises-a base plate9, one end of which is bent upwardly andback'over the top of the base plate to form an upper base plate It].Integrally formed on the inner edge of the top base plate 10 is anupright supporting wall or plate H, which has integrally formed on theupper margin thereof an outwardly projecting upper loop portion [2, intowhich one set of the interfitting loop portions -6 and 1 are adapted toproject, as clearly illustrated :in Figure 1. The

inner end of the top plate of the top loop I2 is bent upwardly toprovide a top flange or wall 13, which is deflected at 1-4 to fit aroundthe flange 3 of one of the interfitting'sections, thereby permitting theupper margin'of theplate 13 to fit or seat against one side of the topfiller or core board 2. The-top loop 12-01 the holderis providedwithopenings I 5, while'the base plate9 andthe upper base plate 10 areprovided with registering openings Hi to permit a tapered channel :pegor stake H to be-projected downwardly through the apertured loopportions of the holder for the purpose of staking one-side of theholderto'the subgrade, Struck outwardly from the intermediate plate of thechannel stake H is a finger or lug l8, which is adapted to seat againstthe top plate of the loop portion I2 to limit the projection ofthe'stake 'l I through the apertured p'ortion'of the holder, The baseplate 9 on the opposite side of the lower core board I is also providedwith an opening Hi to permit another channel stake H to be driventhrough the base plate '9 and into the road subgrade, until theprojecting finger or lug l8 seats against the top of the loop portion 6on that side of the joint mechanism. It will thus be seen that theholders staked in position, as illustrated in Figure 1, serve to holdthe joint forming mechanism properly positioned upon the road subgradeto permit the pouring of concrete on opposite sides of the joint formingmechanism to form the road slabs l9 and 2!]. Asillustrated in Figure l,the major portion of the joint forming mechanism holder is engaged onone side of said mechanism with the base plate 9 projecting from beneaththe slab on one side of the joint beneath the slab on the opposite side.It is intended to position the holdersin staggered reversed position onopposite sides of the joint forming mechanism at spaced intervals,depending upon the length of the expansion joint.

As clearly illustrated in Figure 2, it will be noted that the formationof the expansion joint causes a peculiar formation of the road slabs l9and 20, in whichthe road slab I9 has a portion thereof adjacent theupper core board 2 which overlaps or overhangs the portion of the roadslab 20 which contacts one side of the lower core board I. It will thLLSbe seen that the two overlapping portions of the slabs l9 and 20 areseparated by the slidable contacting plates 8, which connect the twocore board holders forming part of the road joint forming mechanism. Theanchor blades or wings of the interfitting sections are imbedded in therespective slabs I9 and 20, to permit loads to be transmitted from oneroad slab to an adjacent road slab through the overlapping portions ofthe slabs to provide a road construction of materially greater strength,and able to withstand greater shocks and strains before cracking of theroad slabs takes place. The arrangement of the anchoring blades 5, aswell as the offset relation of the core boards I and 2, provides forreinforcement of the road slabs l9 and 20 on opposite sides of the jointfor considerable distances away from the joint.

Figure 3 illustrates a modified form of the load transmission jointimbedded between concrete road slabs 2| and 22, and consisting of acompressible core comprising a lower filler or core board 23, anintermediate filler or core board 24, and an upper filler or core board25. The three core boards are separated by two sets of the interfittingmetal holder sections, which are substantially the same as the sectionsillustrated and described in connection with Figures 1 and 2, with theexception that the cross plates 8 are not as wide as the plates=8illustrated in Figure 1, but are of sufficient width to permit theinterfitting holder sections to position the intermediate core board 24in offset relation with respect to the lower and upper core boards 23and 25 to afford an arrangement where the middle portion of one side ofthe road slab 2| projects between the two sets of interfitting loadtransmission holder sections and between the lower and upper core boards23 and 25s The arrangement illustrated in Figure 3 also permits upperand lower portions of the road slab 22 to project above and below theintermediate core board 24. This arrangement also provides a roadconstruction of greater strength, inasmuch as the slabs 2| and 22 onopposite sides of the joint forming mechanism tend to reinforce theslabs for considerable distances away from the joint so that the road isadapted to withstand greater loads.

In the arrangement illustrated in Figure 3 it will be noted that thecore boards 23, 24, and 25 are so positioned in offset relation withrespect to one another, that one side of the intermediate core board 24is substantially in the plane of one side of the lower and upper coreboards 23 and 25, respectively.

Figure 4 illustrates another modified form of load transmission joint,in which the mechanisms forming the joint are substantially the same asthose described in connection with Figures 1 and 2, with the exceptionthat in this case the connecting plates 8 of the core board supportingsections are of a width permitting the lower core board 26 and the uppercore board 2'. to be offset with respect to one another substantiallyhalf of the thickness of the core boards. This permits portions of theroad slabs 28 and 29 adjacent the joint, to overlap portions of the coreboards 26 and 21, thereby providing a road construction adapted towithstand greater loads and providing a plurality of metal platesbetween the concrete road slabs at the portion of the joint where thecore board holding interfitting sections engage one another.This'modified form of the joint also reinforces the concrete slabs onopposite sides of the joint fora considerable distance away from eachside of the joint.

Figure 5 illustrates a fragmentary sectional view of another modifiedform of an expansion joint forming mechanism substantially the same asthe filler board holding units illustrated in Figures 1 to 4, inclusive.The similar parts are designated by corresponding reference numerals. Inthis modified form of the mechanism the modification consists of the useof a spring steel plate 30 which rests upon the upper common plate 8 ofone of the holder sections and projects into the loop portion 1 which isdisposed directly beneath the upper filler board 2. The use of thespring steel plate 30 reinforces the twointerfitting holder sections andserves to strengthen the middle portion of the joint.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention, and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by the scope of theappended claims.

I claim as my invention:

1. An expansion joint forming mechanism including in combination, aplurality of pre-formed plastic filler boards, load transmitting membersformed for holding the filler boards in offset planes, and holders forsupporting the filler boards and said members in position on a roadsubgrade to be imbedded between concrete road slabs, each of saidholders comprising a pair of loop sections, a wall connecting the same,a flange formed on one of said loop sections, and a base plate formed byan extension of the bottom plate of the other of said loop sections,said base plate extending from beneath one of said road slabs across thebottom of the expansion joint and beneath the opposite road slab.

2, An expansion joint forming mechanism including in combination, aplurality of filler boards, load transmitting members formed for holdingthe filler boards in ofiset parallel planes, holders for supporting thefiller boards and said members in position on a road subgrade to beimbedded between concrete road slabs, each of said holders comprising apair of apertured loop sections, a wall integrally connecting the same,a flange formed on one of said loop sections, an apertured base plateformed by the extension of the bottom plate of the other of said loopsections, said base plate extending from beneath one of said road slabsacross the bottom of the expansion joint and beneath the opposite roadslab, and stake members engaged through the apertured loop sections andthrough the base plate and extending into the road subgrade.

3. In an expansion joint for imbedding between adjacent concrete roadslabs, a plurality of preformed compressible filler boards, slidablyinterfitting load transmitting sections constructed to hold the fillerboards in offset parallel planes and including superimposed platesspanning the space between the offset filler boards, and a spring steelinsert plate for reinforcing the transverse interfitting portions ofsaid sections and interfitting with one of said load transmittingsections and resting upon said superimposed spanning plates.

4. The combination with adjacent concrete road slabs having a pluralityof filler boards therebetween, of load transmitting means anchored inthe slabs onopposite sides of the filler boards and holding said boardsin oifset re1ation,and a spring steel insert plate projectingtransversely between the slabs and between adjacent edges of the fillerboards and supported on the load transmitting means.

ROBERT R. ROBERTSON.

